"For David to beat Goliath, he needed to use a different weapon. If David had used the same weapon, he would have lost the battle. You've got to find your weapons. That's what Brentford is about."

Sitting in his office at the Jersey Road training ground in West London, Rasmus Ankersen, Brentford’s co-director of football, outlines his philosophy of how underdogs can thrive in modern football: by using their brains.

"Brentford can't win by outspending the competition so we have to outthink them. And the question that comes from that is how can we be different? How can we do things in a different way? So, what are the inefficiencies in the system in football, and how can we exploit those?"

Five years ago, Brentford were bought by Matthew Benham, a lifetime fan who made his millions through professional gambling and then a betting company, where he learned the power of numbers to beat human gut instinct. At Brentford, he has set about proving the same thing, transforming the club into one at the cutting edge of analytics. The club, ninth in League One the season before he bought them, were promoted in 2013/14; in 2014/15, they came fifth in the Championship, the first time in 62 years that they had managed a season in the second tier of English football without being relegated.

Ankersen, a ponytailed Dane who has written books on talent and success after a brief football career was ended by injury, was hired two years ago. Brentford have consolidated since, coming ninth and 10th in the last two seasons.

All the while, FC Midtjylland, the Danish club that Benham owns (and where Ankersen is chairman) has provided further vindication of the methods, winning the Danish Superliga for the first time in 2015 and qualifying for the last 32 of the Europa League last year, when they defeated Manchester United in the first leg.

Underdogs rarely win by doing the same things as everyone else. In two centuries of lopsided military battles, Ivan Arreguin-Toft has found that, when the weak tried to do the same as the strong, they lost four times out of five. But when the weak used an unconventional strategy, they won three times out of five. Brentford believe they must be different if they are to defy their budget—Benham vows the club will become self-sustainable, and in any case, financial fair play rules constrain their spending—and reach the top tier in English football for the first time since 1946/47.

Last year brought a salutary reminder of Brentford's status as a glorified feeder club to the giants of English football. Ian Carlo Poveda, a midfield star for England U16s, signed for Manchester City after two years with Brentford.

A few months later, Josh Bohui, a winger who had represented England U17s, was signed by Manchester United. In both cases, Brentford got a minuscule sum in compensation—reportedly about £30,000 apiece. Because players can't sign professional contracts until their 17th birthday, Brentford had no way to protect their investment in players from the age of eight until 16.

"That made us realise that, hey, it's an unfair game," Ankersen told Bleacher Report. "We can't just be on the same playing field as everyone else and doing the same thing, because it's going to cost us a lot of money, and the compensation for those players is not significant. It's not even covering the cost of developing the players."

To maintain their academy, Brentford received a subsidy of £500,000 a year from the Premier League, which they topped up with £1.5 million of their own money each year. Even before last year's two departures to the Manchester clubs, Ankersen and Robert Rowan, Brentford's head of football operations, were doubting whether that represented good value.

As with all academies, most players didn't make the grade—and Brentford couldn't even benefit from the best players the academy produced. Brentford's last youth player to feature regularly for the first team made his debut in 2005.

"The academy model does work for some teams, but for Brentford, it just wasn't right," Rowan said.

Only 26, seven years younger than Ankersen, and with no professional playing experience, Rowan, who previously worked for Stenhousemuir and Celtic, was hired precisely because he is not wedded to the sport's old orthodoxies. "You need to tailor your club based on your requirements, not just based on this model that every club should have," he says. "After 10 years, that's £15 million—could we have spent it on first-team players and got to the Premier League?"

Brentford decided their academy wasn't working. They ditched it completely, losing their Premier League subsidy as a result, but also saving £1.5 million a year of the club's cash.

"If we play the same game, we're not going to win. We need to play another game," Ankersen said. "What we said is, 'OK, let's start on a completely blank sheet of paper. How can we be different here? How can we look at the system and see where the inefficiencies are?' And we said, 'Recruitment.' If you look at the number of players released by Premier League academies, that's a massive number. They make mistakes, because they're making those decisions at an age when relative age, for example, still plays a role. So, the Jamie Vardys of this world, we call the rejects. We like to go pick them up."

With the £1.5 million a year saved, the club decided to do something revolutionary: A B-team focused on players aged 17 to early 20s was launched last summer. The new strategy was created with two targets in mind: "the rejects," players released or unwanted by other English clubs, and overseas players, who would see Brentford as a path to English football, and ultimately the Premier League.

First, the rejects. When they were running their academy, Brentford's location in London was a disadvantage: Their best players were ripe for being picked up by the Premier League elite. But Brentford hope their B-team will use their geography as an advantage by making them uniquely well placed to sign the best academy players released from Premier League clubs, especially in the capital. Left-back Ilias Chatzitheodoridis was recruited from Arsenal last summer.

"Rather than seeing them as an enemy now, we see them as a collaboration partner," Ankersen says. Brentford can help "bigger clubs capitalise on their surplus assets, rather than just releasing them and losing the development costs they had" through selling their players on to Brentford for a small fee or agreeing to a percentage of any future resell.

In March, striker Joe Hardy joined the B-team from Man City U18s. "He was never going to make the first team at Man City, but he has a good chance of making the first team at Brentford," Ankersen says.

Some castoffs Brentford sign may have been rejected for the wrong reasons. In 2015, 45 percent of Premier League academy players were born from September to November, suggesting that many clubs were wrongly preferring bigger and older players over younger and more skilled ones. 

Brentford's approach is a way of guarding against the relative age effect. It is also ideally suited to picking up late developers, who can often usurp prodigies. In Germany, national team footballers had less organised practice than lower-league players in their youth, specialised in football later and only started playing more organised football around age 22.

"We don't cap players—say they must have made it at 21, as some teams do," Rowan says. "It's important not to get caught up in the player's age. If they've got the talent, it will come out at some point."

The B-team system's second great advantage is its appeal to overseas players. The Premier League's sheer wealth and profile renders Brentford's B-team attractive to foreigners who dream of playing there. In fact, their squad includes youth internationals from Denmark and Greece.

In 2016/17, four B-team players represented the first team—more than the number of homegrown players who had made their debuts in one season in over a decade. The B-team are treated less like reserves than a parallel squad to the first team: A B-team player trained with the first team 395 times last season.

"They get educated in the club's philosophy," Ankersen reflects, making "integration a lot more efficient."

Next season, Brentford will try to organise a playing schedule as arduous as the senior team's; one player elevated this year "struggled mentally to adapt" to playing three games a week in the Championship, says Rowan.

The structure enables Brentford to do "succession planning." In Rowan's office is a whiteboard containing a list of 22 players, across all positions, whom the B-team are targeting this summer. The list includes players at English clubs in the Champions League.

B-team players are generally given three-year contracts, and positions with probable vacancies in the first team in the coming years are prioritised; Brentford currently have a shortage of strikers, so Rowan will be willing to pay more for B-team strikers who would have a good chance of progressing. The system also means that Brentford's scouts can identify players not yet ready for the first team who could improve with the B-team.

Ankersen believes Brentford's new strategy enables the club to transform its small size into an advantage.

"The poor are better at making talent than the rich, because they don't have a choice," Ankersen says. "Southampton have a great academy, but why did Gareth Bale, Adam Lallana and that generation end up playing regularly? Because Southampton was in administration. They had to play them. And then they get good.

"You never know with a young player. You never know if he's going to make it before you've given him 35 games. But do you have the guts to give him those 35 games? It’s easier if you don't have a choice. At Chelsea, Man United or Man City, there's so much at stake. Is the risk of bringing a young player on worth it?"

In The Numbers Game: Why Everything You Know About Football Is Wrong, Chris Anderson and David Sally predict that football's biggest analytical breakthroughs will not take place at the richest clubs. Necessity breeds innovation, just as was true for the Oakland Athletics in baseball, or Northamptonshire in English Twenty20 cricket.

Brentford will not be able to compete with richer clubs by doing the same things on a smaller budget. Last season, fellow Championship team Aston Villa spent more on transfer fees than Brentford have in their entire 127-year history but still finished three places lower.

"We think there's a chance we can beat them still, but it takes a lot of hard work," Ankersen says. "It takes a conscious decision on how we want to do things different, how we want to take risks."

In the transfer market, Brentford aim to mimic a shrewd share investor, buying when stocks are low and selling when they are high, using data and analytical thinking to inform their judgements. When Brentford buy, that means a focus on young players and a determination to find undervalued talents, usually on the Continent, where the player market is less inflated than England.

"You want to try to sign players who are in their peak or on their way to their peak rather than being a declining asset," Ankersen explains. "We've got a young team. I think that's the philosophy of the club. We want hungry, energetic players that want to prove themselves, that want to learn, are open-minded to buy into the club's philosophy—doing things different. There's a lot of resale value in the team we have now, and that's the idea as well.”

This season, the average age of Brentford's starting XI was 24 years and 139 days—the second-youngest in the Championship, according to Opta Sports.

The emphasis on youth can cause "natural friction between short term and long term," Ankersen admits.

"A manager might want to have a 29-year-old player who had a cruciate ligament injury two years ago and can probably make a difference now, but does he have any resale value? Will he be a rising financial asset for the club? Those are the questions that we also have to ask. That's why you need someone to think a little bit ahead. We have to sign players that have a resale value."

In general, the best value is on the Continent.

"There are certain leagues in Europe that offer a lot better value for money," Ankersen says, citing Germany. "English players are very, very inflated." The club have tried to sign some young and inexperienced League Two players, only to be told they would cost £2 million.

Ankersen and Brentford use a special tool to identify undervalued talent: a statistical model to compare the relative quality of clubs around the world.

"Basically the question is, if all the teams played in the same league, what would the league table look like? And then you try and identify some of those teams that have more quality than Brentford."

The aim is to find players from clubs above Brentford's level who could be affordable.

The classic case of Ankersen being vindicated here is of FC Midtjylland signing Tim Sparv, a midfielder from a German second-tier team, the summer before they won the Danish title. Midtjylland would never have been able to afford Sparv had he played at one of the leading Danish teams, which ranked similarly to his old club on the model. "Data can tell you where to look, but cannot tell you exactly who to pick."

When signing players, Brentford have another unusual aide: Smartodds, Benham's company, which provides statistical research to gamblers.

In January, the Brentford B-team signed 18-year-old Swedish winger Henrik Johansson, Garrincha's grandson, from Halmstads. Rowan discussed the player with Smartodds' Swedish football analyst and used him to gather information on the player to inform their decision.

"I feel far more confident scouting players here than I've ever felt before because you can get a lot of information to de-risk the decision," Rowan says. "The more information you get, the less risk there is in place. Basically what we're good at is minimising the risk."

While Brentford's approach is informed by numbers, it does not displace human judgement or scouting. "Data is a big part of the recruitment process," Ankersen says. "There's no player I've ever recruited at Brentford without data having its say, but also no player recruited without the traditional method having had a say."

The club analyse players' personalities when they recruit, especially to judge whether foreign players can adapt to a new culture. There are typically 25 scouting reports compiled on each footballer before they join Brentford's first team, and 10 for those joining the B-team. Before players are bought, there is coordination between the coaching staff, scouting department and directors of football.

Ankersen says: "We are quite consensus-seeking in the way we run the recruitment process because if a player's going to make a success, it's the whole environment he's got to buy into."

Yet none of this brings any guarantees.

"Recruitment is about being less and less wrong," Ankersen says. "It's not about being right all the time. Every player you sign is a risk, and you just try and do your due diligence properly."

Like any good stock trader, Brentford also try to sell high, and there is no room for sentiment. In January, Scott Hogan, a striker bought for £750,000 from Rochdale in 2014, was sold to Aston Villa for a reported £15 million in the middle of a hot streak. In the last two years, Brentford have sold significant players in January, when the club recognised there was little chance of either winning promotion or being relegated and viewed the remainder of the season as a good time to incorporate new players.

It is not just in scrapping their academy and their approach to transfers that Brentford are an unusual club. They also measure success differently, not by the league table, but by Ankersen's "table of justice," a variant of the expected goals model. This is informed by the belief that, because football is such a low-scoring sport—the average game has 2.7 goals, compared to over 200 points in basketball—luck is very important. As The Numbers Game notes, favourites win only 65 percent of football matches but 80 percent of basketball games.

Brentford have the confidence to take a long-term view and not allow football's inherent randomness to cloud the club's analysis.

"We don't look so much at the league table position when we evaluate performance. What we look at are the underlying metrics, which we believe are a better indication of where we are going and how we've done," Ankersen says. "We know how we measure performance; we don't overreact to those swings in results that you see that's largely down to randomness, which you see in football because it's a low-scoring sport.

"Telling people that the league table lies is like telling people that the earth is flat. All their preconceptions are being challenged, and the media won't accept it because they rely on having tragedies and triumphs, so it's a difficult thing to say—especially when you are underachieving."

But Brentford do not merely use the "table of justice" as an excuse. In 2015, Mark Warburton was not offered a new contract as manager after Brentford came fifth. The club believed the team had been lucky, that their performances had not merited such impressive results. Warburton was also less enamoured with analytics than other senior figures.

In 2015/16, a record 73 managers left jobs at the 92 clubs in the top four tiers of English football. Ankersen considers this "overreacting," and the compensation that clubs pay sacked managers is seldom a good use of cash, as most managers make little impact for better or worse.

"In football we always want a simple solution to a complex problem—changing the manager," he says.

Dean Smith, Brentford's manager since November 2015, is already among the longest-serving managers in the Championship. Actually, Smith's official job title is head coach, reflecting how Brentford view him: not as a manager in English football's traditional autocratic model but instead part of the club's wider structure. Ankersen believes that most clubs err in giving managers too much power.

"You want to win the game on Saturday, but you can't have someone who makes all the important decisions, and spends the money, with a time horizon of one week. That doesn't make sense," he explains. "You have a manager that's basically in charge of both short-term and long-term football strategy—in some clubs, even responsible for all transfers, finances."

Ankersen likens Brentford's model to a clock: the head coach responsible for the second hand (day-to-day strategy); the directors of football—Ankersen and Phil Giles, who has a Ph.D. in statistics—responsible for the minute hand (medium-term strategy, focused on transfers and succession planning); and the board, including Benham, responsible for the hour hand (long-term strategy and objectives).

"Most clubs who have a managerial structure end up living in the second," Ankersen says.

At Brentford, Smith "doesn't have all these other responsibilities like doing deals, setting out the long-term football strategy—things like that. In that respect, he's got more focused responsibility here than he probably has in other clubs."

Smith was recruited because he was viewed as a head coach who could adapt to Brentford's methods.

"The philosophy of the club remains in place, and then we recruit a coach we think fits into that," Ankersen says. "When we interviewed Dean, we went through all this stuff again and again. We don't think that we have the perfect formula—we are open to his ideas—but generally speaking, he has to execute the club's strategy, and he has to add his way of doing that to it. He's an open-minded guy. That's why he's the head coach."

Brentford don't merely aim to run their club differently, but to also play the game differently. Ankersen is obsessed with "inefficiencies" in how football is played.

Perhaps the biggest is set pieces. "People in football tend to feel that a set-piece goal is not worth as much as a normal goal, which is obviously romance and bulls--t." Ankersen also laments that teams neglect set pieces in training, even though they account for one-third of all goals.

"Could you imagine a company that spends 10 percent of their time on where 35 percent of their revenue comes from? That's what happens in football."

There is, he believes, "big potential" for teams who focus on being more productive from set pieces. As such, Brentford have a set-pieces coach, a ball-striking coach and even used a throw-in coach last summer. Ankersen thinks that ultimately football might have as many special skills coaches as the NFL.

"We are still only scratching the surface of what can be done, but we've got a lot of time and resources dedicated to developing concepts and a framework for set plays," he says. When FC Midtjylland won the Danish league in 2015, almost half of their goals came from set pieces, and Midtjylland also scored nine goals from long throws last season.

"It's a lot of goals," Ankersen says. "It's just a way of being more efficient. When you can't buy a striker for £10 million, you've got to find other ways to get your goals."

The emphasis on set pieces and throws is not only about improving the team, but also increasing players' transfer value if they are sold on. "If you can get a centre-back to score four more goals on set pieces, because you have a strategy, and you've spent time on it, then his value goes up," Ankersen explains.

Brentford are grappling with other questions too. "We have some indication that you can, on some positions, make a difference by making subs earlier than coaches in football tend to do," Ankersen says. He is insatiable in his curiosity.

"There's so much data in football—it's not about the data, it's about how you give meaning to the data. It's about the questions you ask. A lot of data analysts answer a lot of questions, but the problem is no one has asked those questions. So you start with questions that we don't know, that we'd like to know, and then you go into the data."

Of one thing, Ankersen is certain: Football is changing, and clubs need to keep up.

"Psychologists call it the end of history illusion: There's always this thing that you think you reached the top of the mountain, you are the finished article. If you look at football 15 years ago, and you look at football today, you see massive development—much more intensity, higher pace."

Yet few in the sport predict similar evolution in the coming years.

"The question you've got to ask—and it's often not being asked—is if we had to make that development that you are likely to see in 15 years, what does that mean for what we were going to do today?" Ankersen says. "My job sometimes is to try and trigger people to think that way, and think a little bit outside their comfort zone, and what they think is possible."

The last aspect that Brentford think is neglected is improving players.

"Clubs don't see their players enough as financial assets," Ankersen says. "The stock price of this player has to rise while he's here. What has to happen for that to rise? What does he have to improve? How do we get the best of him? That's the questions you've got to ask from a financial point of view.

"Maybe someone has to look at it more from just a football point of view, but I think looking at your player portfolio like a trader would look at his stocks is an interesting idea."

Brentford aim to do so in innovative ways. The club is preoccupied with developing "self-managing athletes": hard workers who eat and sleep sensibly and maintain a lifestyle appropriate for a professional sportsman. Scandinavian players are a particular favourite of Rowan's because they create "less to worry about." There are five Danish and Swedish players across the first team and B-team.

The club are always focused on small ways to gain an edge. They have run cooking classes for players to improve their diets and are currently running a sleep project.

Ankersen explains: "If a player comes in and says, 'I only sleep five hours a night,' you don't want the coach to think, 'Is he not ready to play?' If you can get someone to sleep better and more effectively, he will likely perform better. You try and look at all those factors that add to a player's development."

For all the strides made in how footballers are managed in recent years, Ankersen believes they are generally still in worse condition than leading athletes in other sports. "In terms of professionalism, football is way behind individual sports," he says. "A lot of individual athletes, they are accountable, and make lifestyle choices in a much more effective way than football players.

"If you look at how dedicated some individual athletes are, I don't think many football players come close to that. Cristiano Ronaldo is an outlier in football, with his lifestyle choices and the way he optimises every detail. If he was in swimming, for example, he wouldn't be an exception."

Since Ankersen became co-director in 2015, Brentford have increased the number of hours they train a week.

"We think that we can train more than we do," he says. "Maybe because if you are in an individual sport, you are accountable—if you lose, it comes down to your performance—whereas in football there's 11 players, so it's basically easier to hide. I think players will train a lot more in the future: come into the training ground at 8:00, and not leave before 5:00."

This will not involve a day of conventional training but embracing how new technology can aid footballers. Ankersen thinks that virtual reality—rewatching matches in a gamification environment—and shape work and pattern-recognition exercises will improve players' decision-making.

Underpinning everything that Brentford do is the belief that much of football's conventional wisdom is wrong. "One of our principles is we don't just look at our immediate peers but other sports, other businesses as well," Ankersen says. "There's a lot more people now from the outside coming into football—people with business backgrounds. I think that's really healthy."

The aim is not just to lift Brentford to the Premier League and strike a blow against the logic of financial determinism in football. It is nothing less than to change the sport itself.

"I want to try and do something disruptive to the industry. That's why I'm here," Ankersen says, leaving to study some more numbers. "You've got to change the old habits."

The disruption starts over again in 2017/18 with a pre-season friendly against Aldershot on Friday.

All quotes and information obtained firsthand unless otherwise indicated.